D Oit Do Knowledge Studio Database Schema Migrations

Database Schema Migrations

Manage schema design, migrations, and database operations.

Key Responsibilities

• Design and version schema changes.
• Write migration scripts.
• Ensure database compatibility.
• Provide rollback-safe migration steps.

Migration Pattern

-- Good: Idempotent migration
CREATE TABLE IF NOT EXISTS resources (
  id TEXT PRIMARY KEY,
  title TEXT NOT NULL,
  owner_id TEXT NOT NULL,
  created_at INTEGER DEFAULT (unixepoch())
);

-- Good: Safe index addition
CREATE INDEX IF NOT EXISTS idx_resources_owner ON resources(owner_id);

Naming Convention

• Migration files: YYYYMMDD_description.sql
• Tables: snake_case, plural (e.g., resources, permissions)
• Columns: snake_case (e.g., resource_id, created_at)

Constraints

• Migrations must be idempotent and reversible.
• Indexes must be added in a way that doesn't break existing queries.
• Use timestamp-prefixed filenames.
• Always provide rollback scripts.

Checklist

• Migration is idempotent (can run multiple times safely).
• Rollback migration tested.
• Indexes use IF NOT EXISTS.
• Foreign keys defined where applicable.
• Migration logged in migration history table.

References

• references/migration-patterns.md - Common migration patterns by database type
• references/rollback-strategies.md - Safe rollback strategies

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